Flipping rectangle grid (or flipping tiles) with animation nodes
You can start by inspecting "Transform Individual Polygons" template. THEN, if you are using AN version 1.6, you have this handy pivot thing:

http://animation-nodes-manual.readthedocs.io/en/latest/release_notes/v1_6.html

There is actually an example over there that allows you to flip polygon face. 

A little bit of observation and experimentation and you will have the flip setup.